Printed circuit board having micro strip line, printed circuit board having strip line and method of manufacturing thereof

ABSTRACT

A printed circuit board having a micro strip line, a printed circuit board having a strip line and a method of manufacturing thereof are disclosed. The printed circuit board having a micro strip line in accordance with an embodiment of the present invention includes a first insulation layer, a signal line buried in one surface of the first insulation layer, a plurality of conductors penetrating through the first insulation layer and being disposed on both sides of the signal line in parallel with the signal line, and a ground layer formed to be electrically connected to the conductor on the other surface of the first insulation layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.10-2008-0087265, filed with the Korean Intellectual Property Office onSep. 4, 2008, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND

1. Technical Field

The present invention relates to a printed circuit board having a microstrip line, and a printed circuit board having a strip line and a methodof manufacturing thereof.

2. Description of the Related Art

High performance of a digital device is increasing the frequency of thesignal transmitted between semiconductor devices. Thus, a printedcircuit board having a structure of a micro strip line or a strip lineis now being used in order to transmit a high frequency signal.

FIG. 1 shows a printed circuit board 10 having a micro strip lineaccording to a conventional technology. FIG. 2 shows a printed circuitboard 20 having a strip line according to a conventional technology.

According to the conventional technology, as shown in FIG. 1, a signalline 13 is formed on one surface of an insulation layer 11 and a groundlayer 12 is formed on the other surface of the insulation layer.Otherwise, as shown in FIG. 2, a power layer 24 is formed on one surfaceof the insulation layer 21 and the ground layer 22 is formed on theother surface of the insulation layer 21. A signal line 23 is alsoburied in the insulation layer 21 so that a digital signal istransmitted between semiconductor devices.

However, the conventional technology has a limited maximum bandwidth ofa transmitted signal by causing cross talk between adjacent signal lines13 and 23, and signal transmission distortion, that is, noise due todispersion.

SUMMARY

The present invention provides a printed circuit board having a microstrip line and a printed circuit board having a strip line capable ofreducing both cross talk between signal lines and dispersion, and amethod of manufacturing thereof.

An aspect of the present invention features a printed circuit boardhaving a micro strip line. The printed circuit board in accordance withan embodiment of the present invention can include: a first insulationlayer; a signal line buried in one surface of the first insulationlayer; a plurality of conductors penetrating through the firstinsulation layer and being disposed on both sides of the signal line inparallel with the signal line; and a ground layer formed to beelectrically connected to the conductor on the other surface of thefirst insulation layer.

There are a plurality of the signal lines, and the signal line and theconductor can be alternately disposed.

The signal line can be constituted by a pair of unit signal lines, andthe pair of unit signal lines can be a differential pair.

Each distance between the signal line and the conductors is identical toone another.

Meanwhile, a side of the signal line can face a side of the conductor inparallel.

Also, the width of the signal line can become narrower toward a farthersurface of the insulation layer.

The printed circuit board can further include a second insulation layerformed on the ground layer, and a power layer formed on the secondinsulation layer.

Another aspect of the present invention features a method ofmanufacturing a printed circuit board having a micro strip line. Themethod in accordance with an embodiment of the present invention caninclude: forming a signal line on a carrier; burying the signal line inone surface of a first insulation layer by pressing the carrier onto theone surface of the first insulation layer; forming a plurality ofconductors in the first insulation layer such that the conductorspenetrate through the first insulation layer and are disposed on bothsides of the signal line in parallel with the signal line; and forming aground layer on the other surface of the first insulation layer suchthat the ground layer is electrically connected to the conductor.

Here, the forming of the conductor can include boring a through-hole inthe first insulation layer, and filling the through-hole with aconductive material.

Also, after the forming of the ground layer, the method can furtherinclude forming a second insulation layer on the ground layer, andforming a power layer on the second insulation layer.

Yet another aspect of the present invention features a printed circuitboard having a strip line. The printed circuit board in accordance withan embodiment of the present invention can include: a first insulationlayer, a signal line being buried in one surface of the first insulationlayer; a plurality of conductors penetrating through the firstinsulation layer and being disposed on both sides of the signal line inparallel with the signal line; a ground layer formed on the othersurface of the insulation layer such that the ground layer iselectrically connected to the conductor; a second insulation layerformed on one surface of the first insulation layer such that the secondinsulation layer covers the signal line; and a power layer formed on thesecond insulation layer.

In this case, there are a plurality of the signal lines, and the signalline and the conductor can be alternately disposed.

The signal line can be constituted by a pair of unit signal lines, andthe pair of unit signal lines can be a differential pair.

Each distance between the signal line and the conductors can beidentical to one another.

Meanwhile, a side of the signal line can face a side of the conductor inparallel.

The width of the signal line becomes narrower toward farther the othersurface of the insulation layer.

Still another aspect of the present invention features a method ofmanufacturing a printed circuit board having a strip line. The printedcircuit board in accordance with an embodiment of the present inventioncan include: forming a signal line on a carrier; burying the signal linein one surface of a first insulation layer by pressing the carrier ontothe one surface of the first insulation layer; removing the carrier;forming a plurality of conductors on the first insulation layer suchthat the conductors penetrate through the first insulation layer and aredisposed on both sides of the signal line in parallel with the signalline; forming a ground layer on the other surface of the firstinsulation layer such that the ground layer is electrically connected tothe conductor; forming a second insulation layer on one surface of thefirst insulation layer such that the second insulation layer covers thesignal line; and forming a power layer on the second insulation layer.

In this case, the forming of the conductor can further include boring athrough-hole in the first insulation layer; and filling the through-holewith a conductive material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view showing a printed circuit board havinga micro strip line according to a conventional technology.

FIG. 2 is a cross sectional view showing a printed circuit board havinga strip line according to a conventional technology.

FIG. 3 is a perspective view showing an embodiment of a printed circuitboard having a micro strip line according to an aspect of the presentinvention.

FIG. 4 is a cross sectional view showing an embodiment of a printedcircuit board having a micro strip line according to an aspect of thepresent invention.

FIGS. 5 to 8 are cross sectional views showing transformed shapes of aprinted circuit board having a micro strip line according to an aspectof the present invention.

FIG. 9 is a flowchart showing an embodiment of a method of manufacturinga printed circuit board having a micro strip line according to anotheraspect of the present invention.

FIGS. 10 to 17 are cross sectional views showing processes of anembodiment of a method of manufacturing a printed circuit board having amicro strip line according to another aspect of the present invention.

FIG. 18 is a cross sectional view showing an embodiment of a printedcircuit board having a strip line according to yet another aspect of thepresent invention.

FIGS. 19 to 21 are cross sectional views showing transformed shapes ofan embodiment of a printed circuit board having a strip line accordingto yet another aspect of the present invention

FIG. 22 is a flowchart showing an embodiment of a method ofmanufacturing a printed circuit board having a strip line according tostill another aspect of the present invention.

FIGS. 23 to 30 are cross sectional views showing processes of anembodiment of a method of manufacturing a printed circuit board having astrip line according to still another aspect of the present invention.

DETAILED DESCRIPTION

A printed circuit board having a micro strip line according to thepresent invention, a printed circuit board having a strip line and amethod of manufacturing thereof will be described in detail withreference to the accompanying drawings. In description with reference tothe accompanying drawings, the same reference numerals will be assignedto the same or corresponding element, and repetitive description thereofwill be omitted.

FIG. 3 is a perspective view showing an embodiment of a printed circuitboard 100 having a micro strip line according to an aspect of thepresent invention. FIG. 4 is a cross sectional view showing anembodiment of a printed circuit board 100 having a micro strip lineaccording to an aspect of the present invention.

According to the embodiment of the present invention, provided is aprinted circuit board 100 having a micro strip line. The printed circuitboard includes a first insulation layer 110, a signal line 120 buried inone surface of the first insulation layer 110, a plurality of conductors130 penetrating through the first insulation layer 110 and beingdisposed on both sides of the signal line 120 in parallel with thesignal line 120, and a ground layer 140 formed on the other surface ofthe first insulation layer 110 such that the ground layer iselectrically connected to the conductor 130.

According to such an embodiment of the present invention, cross talkbetween adjacent signal lines 120 and digital signal distortion causedby inductance difference between a high frequency signal and a lowfrequency signal, that is, dispersion are reduced. Consequently, thetransmission quality of a high-speed digital signal can be improved.

Hereinafter, structures of the embodiment of the present invention willbe described in more detail with reference to FIGS. 3 to 8.

The micro strip line structure according to the embodiment of thepresent invention is constituted by the signal line 120, the groundlayer 140, the first insulation layer 110 interposed between the signalline and the ground layer, and the conductor 130 disposed on both sidesof the signal line 120.

The signal line 120 is buried in one surface of the first insulationlayer 110 and a plurality of the signal lines can be formed at apredetermined interval. An alternating current flows through the signalline 120. Cross talk may be created by coupling capacitance formedbetween adjacent signal lines 120. Such a cross talk can be reduced byblocking the space between the signal lines 120 by means of theconductor 130 to be described below. This matter will be described inmore detail in description of the conductor 130.

Additionally, the ground layer 140 is formed on the other surface of thefirst insulation layer 110 such that the ground layer is electricallyconnected to the conductor 130 to be described below. In this case, apart of the ground layer 140 can be used as a current path. This matterwill be described in more detail in description of the conductor 130.

A plurality of the conductors 130 penetrate through the first insulationlayer 110 and are disposed on both sides of the signal line 120 inparallel with the signal line 120. In other words, since the conductor130 is formed to penetrate through one and the other surfaces of thefirst insulation layer 110 and since a pair of the conductors 130disposed on both sides of the signal line 120 on the basis thereof isformed in parallel with the preceding direction of the current in thesignal line 120, the signal line 120 is surrounded by both a pair of theconductors 130 disposed on both sides thereof and the ground layer 140.

Accordingly, with a minimal change of the current path in the groundlayer 140 in accordance with the frequency change of the alternatingcurrent being transmitted to the ground layer 140, the distortion ofdigital signal transfer caused by inductance difference between a highfrequency signal and a low frequency signal, that is, dispersion can bereduced. This matter will be described in more detain in comparison witha conventional technology.

According to a conventional technology, due to both a skin effect, i.e.,a phenomenon in which a high frequency current flows only around thesurface of a conductor and a proximity effect, i.e., a phenomenon inwhich a high frequency current more concentrically flows through a partclose to other conductor, the ground layer 140 has the current path ofthe high frequency current flow which becomes narrower than that of thelow frequency current.

As a result, the high frequency current has a inductance lower than thatof the low frequency current and the transfer speed of the alternatingcurrent changes according to the a frequency. Consequently, dispersionin which a digital signal being transmitted is distorted occurs.

However, according to the embodiment of the present invention, since thesignal line 120 is surrounded by the conductor 130 and the ground layer140, not only the ground layer 140 but also the side of the conductor130 adjacent to the signal line 120 is used as the current path.

That is, the conductor 130 is formed at a distance similar to a distancefrom the signal line 120 to the ground layer 140, so that the side ofthe conductor 130 as well as the ground layer 140 can be used as acurrent path, when not only does the low frequency current flow, butalso the high frequency current flows through the ground layer 140.

As such, with a minimal change of the current path according to thefrequency, the dispersion mentioned above can be remarkably reduced.

Since a resistance can be minimized by using not only the ground layer140 but also the side of the conductor 130 as a current path in the highfrequency, the quality of the digital signal being transmitted can bemore improved.

Here, each distance d1 and d2 between the signal line 120 and theconductors is identical to one another. Therefore, the current pathmentioned above is symmetrical, so that noise can be reduced.Consequently, the quality of the digital signal being transmitted can bemore improved.

Meanwhile, there are a plurality of the signal lines 120. The signalline 120 and the conductor 130 are alternately disposed. Because theconductor 130 performs a function of an obstruction, cross talk betweenthe adjacent signal lines 120 can be reduced.

That is, the signal line 120 is completely buried in the firstinsulation layer 110. The conductor 130 penetrates through the firstinsulation layer 110 and is formed across both surfaces of the firstinsulation layer 110. Finally, the adjacent signal lines 120 areentirely blocked by the conductor 130.

With respect to the adjacent signal lines 120, cross talk is created bycoupling capacitance generated between the adjacent signal lines, sothat noise may occur in the digital signal being transmitted. In orderto prevent said problem, in the embodiment of the present invention, acapacitance is prevented from being formed between the adjacent lines120 by disposing the conductor 130 which blocks the space between aplurality of the signal lines 120. Accordingly, cross talk caused by thecapacitor can be notably reduced.

Next, a transformed shape of the embodiment of the present inventionwill be described with reference to FIGS. 5 to 8 focusing on adifference from the description above.

FIGS. 5 to 8 are cross sectional views showing transformed shapes of aprinted circuit board 100 having a micro strip line according to anaspect of the present invention.

In FIG. 5, a signal line 120 can be constituted by a pair of unit signallines 122 and 124. Such unit signal lines 122 and 124 can be adifferential pair. As a result, even though an alternating currenttransmitted to one unit signal line 122 by noise is changed, the otherunit signal line 124 is changed, compensating for the change.Eventually, the quality of the digital signal being transmitted can beimproved.

Besides, in FIG. 6, the side of the signal line 120 faces the side ofthe conductor 130 in parallel. The width of the signal line 120 becomesnarrower toward the other surface of the insulation layer, such that thecross-section of the signal line 120 can have a trapezoidal shape. Asthe side of the signal line 120 faces the side of the conductor 130 inparallel, a certain distance between the signal line and the conductorcan be maintained. Accordingly, the occurrence of noise can be reducedand a high-quality digital signal can be more efficiently transmitted.

As shown in FIG. 6, the side of the signal line 120 faces the side ofthe conductor 130 in parallel as well as the width of the lower part ofthe signal line 120 is narrower than that of the upper part of thesignal line. Thus, a distance from each point of the surface of thesignal line 120 to both the ground layer 140 and the conductor 130 canbe relatively and uniformly maintained. Accordingly, the occurrence ofnoise can be reduced and a digital signal can be more efficientlytransmitted.

In this case, as shown in FIG. 6, the width of the conductor 130 becomesnarrower toward the upper part from the lower part. As a result, sinceone surface of the first insulation layer 110 has an increasing space,the degree of density of the signal line 120 buried in one surface ofthe first insulation layer 110 can be increased.

In FIG. 7, shown are a signal line 120 having a trapezoidalcross-section and unit signal lines 122 and 124 being a differentialpair. The detailed description thereof will be omitted.

As shown in FIG. 8, the printed circuit board 100 according to theembodiment of the present invention can further include a secondinsulation layer 150 formed on the ground layer 140 and a power layer160 formed on the second insulation layer 150.

Next, an embodiment of a method of manufacturing a printed circuit board200 having a micro strip line according to another aspect of the presentinvention will be described.

FIG. 9 is a flowchart showing an embodiment of a method of manufacturinga printed circuit board 200 having a micro strip line according toanother aspect of the present invention. FIGS. 10 to 17 are crosssectional views showing processes of an embodiment of a method ofmanufacturing a printed circuit board 200 having a micro strip lineaccording to another aspect of the present invention.

According to the embodiment of the present invention, provided is amethod of manufacturing a printed circuit board 200 having a micro stripline. The method includes forming a signal line 220 on a carrier 205,burying the signal line 220 in one surface of a first insulation layer210 by pressing the carrier 205 onto the one surface of the firstinsulation layer 210, forming a plurality of conductors 230 in the firstinsulation layer 210 such that the conductors penetrate through thefirst insulation layer 210 and are disposed on both sides of the signalline 220 in parallel with the signal line 220, and forming a g roundlayer 240 on the other surface of the first insulation layer 210 suchthat the ground layer is electrically connected to the conductor 230.

According to such an embodiment of the present invention, it is possibleto implement the printed circuit board 200 reducing cross talk betweenadjacent signal lines 220 and digital signal distortion caused byinductance difference between a high frequency signal and a lowfrequency signal, that is, dispersion.

Hereinafter, each process will be described in detail with reference toFIGS. 9 to 17.

First, as shown in FIG. 10, the signal line 220 is formed on the carrier205 (S110). For example, the signal line 220 is formed on the carrier205 by using electrolytic plating. In addition, the signal line 220 canbe also formed by using various processes such as a subtractive process,an inkjet process and the like.

Subsequently, as shown in FIG. 11, the signal line 222 is buried in onesurface of the first insulation layer 210 by pressing the carrier 205onto the one surface of the first insulation layer 210 (S120). This is aprocess of heating and compressing the carrier 205 and the firstinsulation layer 210 in order to bury the signal line 220 in one surfaceof the first insulation layer 210. By using the carrier 205 mentionedabove, it is possible to more easily bury the signal line 220 in thefirst insulation layer 210 and to enhance the adhesive strength betweenthe signal line 220 and the first insulation layer 210.

As shown in FIG. 12, the carrier 205 is removed (S130). This is aprocess of exposing the signal line 220 to the outside. The signal linecan be exposed by separating the carrier 205 or by etching and removingthe carrier.

As shown FIGS. 13 and 14, a plurality of the conductors 230 are formedin the first insulation layer 210 such that the conductors penetratethrough the first insulation layer 210 and are disposed on both sides ofthe signal line 220 in parallel with the signal line 220 (S140). Here,the conductors 230 are disposed on both sides of the signal line 220 andare extended in parallel with the current proceeding direction of thesignal line 220, so that the conductor surrounds the signal line 220together with the ground layer 240. The conductor 230 is disposed in thespace between a plurality of the signal lines 220 and blocks the spacebetween the signal lines 220. As a result, the conductor 230 can reducethe dispersion and cross talk. As the one embodiment mentioned above hasdescribed the subject, the more detailed description thereof will beomitted.

The process of forming the conductor 230 mentioned above can bedescribed as below stage by stage.

First, as shown in FIG. 13, a through-hole 232 is bored in the firstinsulation layer 210 (S142). In other words, the through-hole 232 isbored in the first insulation layer 210 such that the signal line 220can be disposed between the conductors 230. Subsequently, as shown inFIG. 14, the through-hole 232 is filled with a conductive material(S144). For example, the through-hole can be filled by plating theinside of the through-hole 232 or by filling the inside of thethrough-hole 232 with a conductive paste.

As shown in FIG. 15, the ground layer 240 is formed on the other surfaceof the first insulation layer 210 such that the ground layer iselectrically connected to the conductor 230 (S150). For example, theground layer can be formed by plating the other surface of the firstinsulation layer 210 or by laminating copper foil on the other surfaceof the first insulation layer.

In such a ground layer 240, a part of the ground layer is used as acurrent path. The conductor 230 mentioned above is electricallyconnected to the ground layer 240 so that the conductor as well as theground layer 240 can be also used as a current path.

As shown in FIG. 16, a second insulation layer 250 is formed on theground layer 240 (S160). This is a process of forming the secondinsulation layer 250 on the ground layer 240 which has been formed inthe previous process. For example, the process can be performed bylaminating the second insulation layer 250 on the ground layer 240.

As shown in FIG. 17, a power layer 260 is formed on the secondinsulation layer 250 (S170). This is a process of forming the powerlayer 260. For example, the power layer 260 can be formed by plating theother surface of the second insulation layer 250 or by laminating copperfoil on the second insulation layer 250.

In the embodiment of the present invention, it has been provided as anexample that a method of performing a process S140 of forming aplurality of the conductors 230 in the first insulation layer 210 afterperforming the process S120 of burying the signal line 220 on onesurface of the first insulation layer 210. However, on the contrary, theprocess S120 of burying the signal line 220 can be performed afterperforming the process S140 of forming a plurality of the conductors230, which also belongs to the scope of rights of the present invention.

In the mean time, as shown in FIGS. 3 to 7, it is possible tomanufacture a printed circuit board (see reference numeral 100 in FIGS.3 to 7) having various types of micro strip lines. Since a process ofmanufacturing the printed circuit board is the same as or similar tothat of the embodiment of the present invention, descriptions thereofwill be omitted.

Next, an embodiment of a printed circuit board 300 having a strip lineaccording to yet another aspect of the present invention will bedescribed.

FIG. 18 is a cross sectional view showing an embodiment of a printedcircuit board 300 having a strip line according to yet another aspect ofthe present invention. FIGS. 19 to 21 are cross sectional views showingtransformed shapes of an embodiment of a printed circuit board 300having a strip line according to yet another aspect of the presentinvention

According to the embodiment of the present invention, as shown in FIG.18, provided is a printed circuit board 300 having a strip line. Theprinted circuit board includes a first insulation layer 310, a signalline 320 buried in one surface of the first insulation layer 310, aplurality of conductors 330 penetrating through the first insulationlayer 310 and being disposed on both sides of the signal line 320 inparallel with the signal line 320, a ground layer 340 formed on theother surface of the first insulation layer 310 such that the groundlayer is electrically connected to the conductor 330, a secondinsulation layer 350 formed on one surface of the first insulation layer310 such that the second insulation layer covers the signal line 320,and a power layer 360 formed on the second insulation layer 350.

According to such an embodiment of the present invention, cross talkbetween adjacent signal lines 120 and digital signal distortion causedby inductance difference between a high frequency signal and a lowfrequency signal, that is, dispersion are reduced. Consequently, thetransmission quality of a high-speed digital signal can be improved.

In the embodiment of the present invention, since the configuration andconsequent functions of the first insulation layer 310, the signal line320, the unit signal lines 322 and 324, the conductor 330 and the groundlayer 340 have been described in the one embodiment of the printedcircuit board (see reference numeral 100 in FIGS. 3 to 7) having themicro strip line described above, descriptions thereof will be omitted.Hereinafter, a difference from the embodiment of the present invention,that is, the second insulation layer 350 and the power layer 360 will bedescribed.

The second insulation layer 350 is formed on one surface of the firstinsulation layer 310 such that the second insulation layer covers thesignal line 320. The power layer 360 is formed on such a secondinsulation layer 350. Therefore, it is possible to form a strip linestructure having the signal line 320 buried between the first insulationlayer 310 and the second insulation layer 350, the ground layer 340formed on the other surface of the first insulation layer 310, and thepower layer 360 formed on the second insulation layer 350.

Next, an embodiment of a method of manufacturing a printed circuit board400 having a strip line according to still another aspect of the presentinvention will be described.

FIG. 22 is a flowchart showing an embodiment of a method ofmanufacturing a printed circuit board having a strip line according tostill another aspect of the present invention. FIGS. 23 to 30 are crosssectional views showing processes of an embodiment of a method ofmanufacturing a printed circuit board having a strip line according tostill another aspect of the present invention.

According to the embodiment of the present invention, provided is amethod of manufacturing a printed circuit board 400 having a strip line.The method includes forming a signal line 420 on a carrier 405, forminga plurality of conductors 430 on a first insulation layer 410 such thatthe conductors penetrate through the first insulation layer 410 and aredisposed on both sides of the signal line 420 in parallel with thesignal line 420, burying the signal line 420 in one surface of a firstinsulation layer 410 by pressing the carrier 405 onto the one surface ofthe first insulation layer 410, removing the carrier 405, forming aground layer 440 on the other surface of the first insulation layer 410such that the ground layer is electrically connected to the conductor430, forming a second insulation layer 450 on one surface of the firstinsulation layer 410 such that the second insulation layer covers thesignal line 420, and forming a power layer 460 on the second insulationlayer 450.

According to such an embodiment of the present invention, it is possibleto implement the printed circuit board 400 reducing cross talk betweenadjacent signal lines 420 and digital signal distortion caused byinductance difference between a high frequency signal and a lowfrequency signal, that is, dispersion.

In the embodiment of the present invention, since the one embodiment ofthe method of manufacturing the printed circuit board 400 (see referencenumeral 200 of FIG. 17) having the strip line mentioned above hasdescribed the process S210 of forming the signal line 420 on the carrier405 as shown in FIG. 23, the process S220 of forming a plurality ofconductors 430 in the first insulation layer 410 by boring athrough-hole 432 in the first insulation layer 410 (S222) as shown inFIG. 24 and by filling the through-hole 432 with a conductive material(S224) as shown in FIG. 25, the process S230 of burying the signal line420 in one surface of the first insulation layer 410 as shown in FIG.26, the process S240 of removing the carrier 405 as shown in FIG. 27,and the process S250 of forming the ground layer 440 on the othersurface of the first insulation layer 410 as shown in FIG. 28,descriptions thereof will be omitted. Hereinafter, differences from theembodiment of the present invention, that is, a process S260 of formingthe second insulation layer 450 and a process S270 of forming the powerlayer 460 will be described.

After forming the ground layer 440, as shown in FIG. 29, the secondinsulation layer 450 is formed on one surface of the first insulationlayer 410 such that the second insulation layer covers the signal line420 (S260). This is a process of forming the second insulation layer 450to cover the signal line 420 in order to completely bury the signal line420. For example, the process can be performed by laminating asemi-cured second insulation layer 450 on one surface of the firstinsulation layer 410.

Next, as shown in FIG. 30, the power layer 460 is formed on the secondinsulation layer 450 (S270). This is a process of completing a stripline structure by forming the power layer 460 on the second insulationlayer 450. For example, the power layer 460 can be formed by plating thesecond insulation layer 450 or by laminating copper foil on the secondinsulation layer 450.

In the embodiment of the present invention, it has been provided as anexample that a method of performing a process S230 of burying the signalline 420 on one surface of the first insulation layer 410 afterperforming a process S220 of forming a plurality of the conductors 430on the first insulation layer 410. However, on the contrary, the processS220 of forming a plurality of the conductors 430 can be performed afterthe process S230 of burying the signal line 420, which also belongs tothe scope of rights of the present invention.

In the mean time, as shown in FIGS. 19 to 21, it is possible tomanufacture a printed circuit board (see reference numeral 300 in FIGS.19 to 21) having various types of micro strip lines. Since a process ofmanufacturing the printed circuit board is the same as or similar tothat of the embodiment of the present invention, descriptions thereofwill be omitted.

While the one embodiment of the present invention has been described, itis possible for those skilled in the art to make various changes andmodifications of the forms and details of the present invention by meansof addition, change, elimination or supplement, etc., of the componentsof the present invention without departing from the spirit of thepresent invention as defined by the appended claims, which also belongsto the scope of rights of the present invention.

1. A printed circuit board having a micro strip line, comprising: afirst insulation layer; a signal line buried in one surface of the firstinsulation layer; a plurality of conductors penetrating through thefirst insulation layer and being disposed on both sides of the signalline in parallel with the signal line; and a ground layer formed to beelectrically connected to the conductor on the other surface of thefirst insulation layer.
 2. The printed circuit board of claim 1, whereinthere are a plurality of the signal lines, and the signal line and theconductor are alternately disposed.
 3. The printed circuit board ofclaim 1, wherein the signal line is constituted by a pair of unit signallines, and the pair of unit signal lines is a differential pair.
 4. Theprinted circuit board of claim 1, wherein each distance between thesignal line and the conductors is identical to one another.
 5. Theprinted circuit board of claim 1, wherein a side of the signal linefaces a side of the conductor in parallel.
 6. The printed circuit boardof claim 5, wherein the width of the signal line becomes narrower towardthe other surface of the insulation layer.
 7. The printed circuit boardof claim 1, further comprising: a second insulation layer formed on theground layer; and a power layer formed on the second insulation layer.8. A method of manufacturing a printed circuit board having a microstrip line, the method comprising: forming a signal line on a carrier;burying the signal line in one surface of a first insulation layer bypressing the carrier onto the one surface of the first insulation layer;forming a plurality of conductors in the first insulation layer suchthat the conductors penetrate through the first insulation layer and aredisposed on both sides of the signal line in parallel with the signalline; and forming a ground layer on another surface of the firstinsulation layer such that the ground layer is electrically connected tothe conductor.
 9. The method of claim 8, wherein the forming of theconductor comprises: boring a through-hole in the first insulationlayer; and filling the through-hole with a conductive material.
 10. Themethod of claim 8, further comprising, after the forming of the groundlayer: forming a second insulation layer on the ground layer; andforming a power layer on the second insulation layer.
 11. A printedcircuit board having a strip line, comprising: a first insulation layer,a signal line being buried in one surface of the first insulation layer;a plurality of conductors penetrating through the first insulation layerand being disposed on both sides of the signal line in parallel with thesignal line; a ground layer formed on the other surface of theinsulation layer such that the ground layer is electrically connected tothe conductor; a second insulation layer formed on one surface of thefirst insulation layer such that the second insulation layer covers thesignal line; and a power layer formed on the second insulation layer.12. The printed circuit board of claim 11, wherein there are a pluralityof the signal lines, and the signal line and the conductor arealternately disposed.
 13. The printed circuit board of claim 11, whereinthe signal line is constituted by a pair of unit signal lines, and thepair of unit signal lines is a differential pair.
 14. The printedcircuit board of claim 11, wherein each distance between the signal lineand the conductors is identical to one another.
 15. The printed circuitboard of claim 11, wherein a side of the signal line faces a side of theconductor in parallel.
 16. The printed circuit board of claim 15,wherein the width of the signal line becomes narrower toward farther theother surface of the insulation layer.
 17. A method of manufacturing aprinted circuit board having a strip line, the method comprising:forming a signal line on a carrier; burying the signal line in onesurface of a first insulation layer by pressing the carrier onto the onesurface of the first insulation layer; removing the carrier; forming aplurality of conductors on the first insulation layer such that theconductors penetrate through the first insulation layer and are disposedon both sides of the signal line in parallel with the signal line;forming a ground layer on the other surface of the first insulationlayer such that the ground layer is electrically connected to theconductor; forming a second insulation layer on one surface of the firstinsulation layer such that the second insulation layer covers the signalline; and forming a power layer on the second insulation layer.
 18. Themethod of claim 17, wherein the forming of the conductor comprises:boring a through-hole in the first insulation layer; and filling thethrough-hole with a conductive material.